The embodiments described herein relate generally to a wind turbine rotor blade and, more particularly, to a sparcap system for a wind turbine rotor blade.
At least some known wind turbine rotor blades include two blade shell portions of fiber reinforced polymer. The blade shell portions are molded and then coupled together along cooperating edges using a suitable adhesive material. The blade shell portions typically include panel walls that are made using suitable, evenly distributed fibers, fiber bundles, or mats of fibers layered in a mold part. However, the panel walls are relatively light and have only low rigidity. Therefore, a stiffness and a rigidity, as well as a buckling strength, of the panel walls may not withstand the loads and forces exerted on the rotor blade during operation. To increase the strength of the rotor blade, the blade shell portions are reinforced by sparcaps laminated to the inner surface of the blade shell portions. Typically, the sparcaps extend substantially along a longitudinal length of the rotor blade. At least some known rotor blades include sparcaps with symmetrical cross-section widths and approximately equal cross-section areas. At least some known sparcaps are fabricated from suitable glass material.
Flapwise loads, which cause the rotor blade tip to deflect towards the wind turbine tower, are transferred along the rotor blade predominantly through the sparcaps. Further, with a continuously increasing length of wind turbine rotor blades in recent years, meeting stiffness requirements is a major concern in the structural design of the rotor blade. As such, conventional blade designs are either over-strengthened resulting in a heavier design or over-stiffened resulting in a costly design. In addition, conventional rotor blade designs include thicker panel walls and/or larger panel wall lengths so that panel walls are comparatively more expensive than sparcaps. At least some known wind turbine rotor blades include panel walls that are fabricated from suitable balsa material, which is relatively more expensive than sparcap material.